electricians mate in need of your help

[peteslade]

Hi there;

Im currently studying the 2330 electrical installation course and am in the process of testing my bay assignment.I have managed to test the lighting and power circuits,but i am unsure of how i carry out an insulation resistance test on the 4.0mm swa cable which is a sub-main cable fed via a 50 amp mcb from the main board.Please could somebody give me a step by step guide,I HAVE TO FINISH BY TOMMORROW 09/062010.THANKS

 

[Spa Key]

Hi there;

Im currently studying the 2330 electrical installation course and am in the process of testing my bay assignment.I have managed to test the lighting and power circuits,but i am unsure of how i carry out an insulation resistance test on the 4.0mm swa cable which is a sub-main cable fed via a 50 amp mcb from the main board.Please could somebody give me a step by step guide,I HAVE TO FINISH BY TOMMORROW 09/062010.THANKS

Is this for your 206? If so, disconnect at the supply end and do your normal R1+R2 and IR. Treat the supply end as your CU (i.e. link-out there).

I don't think the 206 involves live testing; does yours?

Edit: Just read you only want to IR it. As long as you do it from the dead side of the isolator, switch off the isolator at your sub-board and do the IR test as you normally would.

 

[JUD]

Hi there;

Im currently studying the 2330 electrical installation course and am in the process of testing my bay assignment.I have managed to test the lighting and power circuits,but i am unsure of how i carry out an insulation resistance test on the 4.0mm swa cable which is a sub-main cable fed via a 50 amp mcb from the main board.Please could somebody give me a step by step guide,I HAVE TO FINISH BY TOMMORROW 09/062010.THANKS

I don't think you should be protecting a 4mm² cable with a 50A MCB

 

[Sintra]

Also make sure you test between all conductors and the steel armour when doing your IR tests.

 

[Sintra]

2 core 4mm SWA in free air or cable tray Ref method E is 52A for 90 degree swa

 

[JUD]

2 core 4mm SWA in free air or cable tray Ref method E is 52A for 90 degree swa

I stand corrected. Although he didn't actually state he was using 90°C cable, I just assumed it was 70°C.

Sorry...

 

[peteslade]

I don't think you should be protecting a 4mm² cable with a 50A MCB

The 50 amp mcb is what is pre installed before exam starts.

 

[Bromd123]

I have just done my 206 and we had 6mm "tails" and 4mm earth running through steel conduit as pvc single protected by a 32 amp breaker

How did you get on by the way?

 

[peteslade]

Its all done now,fortunatly one of my friends is 2391 qualified.Thanks for the post.